使用HTTP协下载文件

提示：扫一扫查出行
【扫一扫了解最新限行尾号】
复制提示

通过发送HTTP请求，下载文件

头文件：

#ifndef __HTTP__
#define __HTTP__ #include <stdio.h>
#include <stdlib.h>
#include <string>
#include <winsock.h> using namespace std; /**
* URL相关数据
*/
typedef struct _URLData {
string url; // 完整的url地址
string path; // 文件路径
string host; // 主机名
string ip; // 点分隔的ip
int port; // 端口
string resName; // 资源名字
} URLData; /**
* 解析url
*/
void parseURL(string url, URLData* data); /**
* 链接http服务器
*/
bool connectHttpServer(int socketId, string ip, int port); /**
* 生成请求文本
*/
void generateRequestTxt(URLData* data, string* requestTxt); /**
* 发送http请求
*/
bool sendHttpRequest(int socketId, string* requestTxt); /**
* 接受响应数据
*/
void recvHttpResponse(int socketId, string* responseTxt); /**
* 保存http数据
*/
bool saveHttpData(string* responseTxt, string filePath = "", string fileName = ""); /**
* 获取http资源
*/
bool getHttpResource(string url, string filePath = "", string fileName = ""); #endif

代码文件：

#include "http.h"
#include "DNS/DNS.h"
#include "time.h" /**
* 解析url
*/
void parseURL(string url, URLData* data)
{
int startPos = ;
string begin = url.substr(, );
if (begin == "http") {
startPos = ;
} int i = startPos;
int lastSplitPos = ;
for (int len = url.length(); i<len; i++) {
unsigned char ch = url.at(i); if (ch == ) {
if (data->host.length() == ) {
data->host = url.substr(startPos, i - startPos);
data->path = url.substr(i, url.length() - i); break;
} lastSplitPos = i;
}
}
// data->path = url.substr(iPath, url.length() - iPath);
data->url = url;
data->port = ; int resNameLastPos = url.length()-;
int resNameFirstPos = ;
for (int i = url.length()-; i>=; i--) {
unsigned char ch = url.at(i); if (ch == '.')
resNameLastPos = i;
else if (ch == '/') {
resNameFirstPos = i + ;
break;
}
}
data->resName = url.substr(resNameFirstPos, resNameLastPos - resNameFirstPos);
} /**
* 链接HTTP服务器
*/
bool connectHttpServer(int socketId, string ip, int port)
{
// 初始套接字化地址
struct sockaddr_in serverAddr;
memset(&serverAddr, , sizeof(serverAddr));
serverAddr.sin_family = AF_INET;
serverAddr.sin_addr.S_un.S_addr = inet_addr(ip.c_str());
serverAddr.sin_port = htons(port); if (connect(socketId, (struct sockaddr*)&serverAddr, sizeof(serverAddr)) == SOCKET_ERROR) {
return false;
}
return true;
} /**
* 生成请求文本
*/
void generateRequestTxt(URLData* data, string* requestTxt)
{
requestTxt->append("GET "); requestTxt->append(data->path); requestTxt->append(" HTTP/1.1\r\n");
requestTxt->append("Host: "); requestTxt->append(data->host); requestTxt->append("\r\n");
requestTxt->append("Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8\r\n");
requestTxt->append("Accept-Language: zh-CN,zh;q=0.8\r\n");
requestTxt->append("User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/28.0.1500.72 Safari/537.36\r\n");
requestTxt->append("Accept-Encoding: deflate,sdch\r\n");
requestTxt->append("Connection: close\r\n\r\n");
} /**
* 发送http请求
*/
bool sendHttpRequest(int socketId, string* requestTxt)
{
int sendBytes = send(socketId, requestTxt->c_str(), requestTxt->length(), );
return sendBytes > ;
} /**
* 接受响应数据
*/
void recvHttpResponse(int socketId, string* responseTxt)
{
char buff[]; int recvBytes = ;
while ((recvBytes = recv(socketId, buff, , )) > ) {
responseTxt->append(buff, recvBytes);
}
} /**
* 保存http数据
*/
bool saveHttpData(string* responseTxt, string filePath, string fileName)
{
if (fileName == "") {
char _fileName[];
sprintf(_fileName, "%lld", time());
fileName = _fileName;
} string fileExt = "."; int i = , len = ;
for (i = , len = responseTxt->length(); i<len; i++) {
unsigned char ch = responseTxt->at(i); if (ch == 'C') {
unsigned char metaKey[], typeMetaKey[] = "Content-Type";
memset(metaKey, , );
memcpy(metaKey, responseTxt->c_str() + i, ); string metaValue;
if ( strcmp((char*)metaKey, (char*)typeMetaKey) == ) {
for (int j = i+;;j++) {
unsigned char ch = responseTxt->at(j); metaValue.push_back(ch);
if (ch == '\r') {
for (int k = , len = metaValue.length(); k<len; k++) {
if (metaValue.at(k) == '/') {
fileExt.append( metaValue.substr(k+, metaValue.length() - k - ) );
fileName.append(fileExt); break;
}
} break;
}
}
}
} if (ch == '\r' &&
responseTxt->at(i+) == '\n' &&
responseTxt->at(i+) == '\r' &&
responseTxt->at(i+) == '\n') {
i += ;
break;
}
} FILE* fp = fopen((filePath + fileName).c_str(), "wb+");
if (fp) {
fwrite(responseTxt->c_str() + i, , responseTxt->length() - i, fp);
fclose(fp); return true;
}
return false;
} /**
* 获取http资源
*/
bool getHttpResource(string url, string filePath, string fileName)
{
printf("-------------------------------------\n"); int socketId = socket(AF_INET, SOCK_STREAM, );
if (socketId == INVALID_SOCKET) {
printf("Create sokcet failed\n"); return false;
} // 解析url数据
URLData data;
parseURL(url, &data); // 获取DNS信息
if (!getIPAddrByDNS(data.host, &data.ip)) {
printf("Get ip(%s) from DNS server failed\n", data.host.c_str()); return false;
} // 生成请求文本
string requestTxt;
generateRequestTxt(&data, &requestTxt); // 链接服务器
if (!connectHttpServer(socketId, data.ip, data.port)) {
printf("Connect http server failed, ip:%s\n", data.ip.c_str()); return false;
} printf("Send http request:\n%s\n", requestTxt.c_str()); // 发送请求
if (!sendHttpRequest(socketId, &requestTxt)) {
printf("Send http request failed\n"); return false;
} // 接受响应
string responseTxt;
recvHttpResponse(socketId, &responseTxt); printf("Recive http response:\n%s\n", responseTxt.c_str()); // 保存数据
if (!saveHttpData(&responseTxt, filePath, (fileName.length() == ) ? data.resName : fileName)) {
printf("Save response data failed\n");
return false;
} closesocket(socketId); printf("-------------------------------------\n"); return true;
}